Could bees be the key to better biosecurity?

Scientists are exploring whether these tireless workers of our fields, forests and orchards might also be able to pick up any costly new incursions.

New Zealand currently spends nearly $250 million on surveillance, eradication and management programmes – and a string of unwanted visitors to our shores has only heaped on more pressure.

They included cropping pest velvetleaf, wind-blown fungal scourge myrtle rust and the cattle bacterial disease M.bovis, which has already cost $800m and counting.


Dr Andrew Cridge, of Otago University's School of Biochemistry, said such incursions were tough to contain once they had crossed into the country.

That meant the best chance of a successful eradication was rapid detection.

But when it came to noxious weeds that could cause big headaches for the primary sector, our monitoring system wasn't fool-proof and largely relied on chance observations and border interceptions.

In honeybees, Cridge saw a clever way to quickly tell if we had a new troublesome weed on our hands.

In a major new project, his team would use bees to gather pollen from a dozen rural and urban sites around the country, including high-risk spots for exotic weed invasions.

Next, the researchers would apply next-generation DNA sequencing to classify the gathered pollen and reveal if they had come from any of the weeds.

"This will not only allow us to identify plant species that have evaded detection and established in the wild, but determine the range of the incursion."

A unique part of the study was its use of a specially-developed approach dubbed "metabarcoding", which could accurately characterise the pollen.

"DNA metabarcoding can provide higher-resolution identification of pollen at a scale and sensitivity not possible through traditional identification methods, such as microscopy."

Cridge described it as a means of identifying organisms based on differences that showed up in their sequenced DNA.

"We have used DNA metabarcoding previously to identify which plant species native moths pollinate."

In this case, they hoped to develop the approach to the point where it could be used as a surveillance tool, either at border control or across high-risk sites, such as areas where international tourists camped on their first night in the country.

"Also, we would like to see it used for identification and eradication programs in the field for plants like Saffron thistle and velvetleaf," Cridge said.

"Ideally, we would like to see the metabarcoding test taken up by the Ministry for Primary Industries and others as an additional low cost bio-monitoring system."

With increasing trade and tourism, along with the sweeping impacts of climate change, Cridge said more big incursions were inevitable.

"A new plant species establishes in the wild every 39 days – and these can cause ecological damage, while also having a negative impact on the economy and human health," he said.

"If we can intercept or eradicate even one noxious plant species, we will make an impact."

The study is being supported with a $964,000 grant from the Ministry of Business, Innovation and Employment's Endeavour Fund.